Quantification De L’erosion Hydrique En Utilisant Le Modèle Rusle Et Déposition Intégrée Dans Un Sig. Cas Du Bassin Versant De L’oued Isly (Maroc Oriental)

In Morocco, hydric erosion is the main factor in soil degradation. It is a dynamic and very complex phenomenon, linked to natural and anthropic factors that are difficult to control in time and space. Land degradation has visible impacts on the environment and hinders economic and social development. The consequences of erosion, both upstream and downstream of watersheds, are costly for the Moroccan economy. The Oued Isly watershed is an elongated mountan basin with an area of 1312km2. It is part of eastern Morocco. It is located in the south of Oujda city. Wadi Isly is characterized by irregular flow. Its flow increases during the winter and early spring. Extreme flows are recorded after exceptional and very intense rain in the Touissit and Guenfouda mountains. The watershed of Wadi Isly knows currently a very active erosive dynamic that affects all the slopes on both banks of the Oued Isly. Several factors contribute to the processes of soil degradation, such as climatic aggression and anthropogenic action. The objective of this study is to estimate soil losses at the Wadi Isly watershed by the application of the universal soil loss equation (USLE) and the use of GIS and Remote sensing. This study also aims to discuss the amplifying factors of the erosive phenomenon in this semi-arid environment

Patrimoine et développement local à Fès : priorités, acteurs et échelles d’action

L’article présente les priorités qui s’inscrivent dans la stratégie de sauvegarde et de valorisation du patrimoine urbain de la Médina de Fès. Deux principales approches différentes ont été reconnues au cours des dernières décennies. La première est mise en œuvre entre 1980 et 2000 et se caractérise par des actions ponctuelles de réhabilitation et de sauvegarde. L’article présente leurs acteurs et discute la superposition des niveaux de leur action. L’implication des acteurs locaux, régionaux et nationaux dans la sauvegarde de ce patrimoine classé sur la liste du patrimoine mondial de l’Unesco ainsi que l’intérêt porté à celle-ci par les organismes internationaux ont été observés. La seconde approche a été notée depuis 2000, car la conception et l’action dans le domaine du patrimoine et du développement local privilégient la programmation régionale et sectorielle, l’action sociale et le développement humain. Parmi les actions prioritaires actuellement mises en chantier, l’article présente deux plans régionaux, le PDRT (plan régional du développement du tourisme) et le PDRA (plan régional de développement de l’artisanat), et évoque l’intérêt porté à la réhabilitation du tissu urbain historique et la lutte contre l’habitat insalubre. Les besoins qui s’expriment dans le domaine de la réhabilitation de la Médina sont énormes en raison de ses multiples processus de dégradation. Faute de moyens financiers et d’une meilleure coordination des interventions, l’action des acteurs locaux n’arrive pas à surmonter ces défis. Vue l’ampleur de ces besoins, des interventions de niveaux plus élevés sont nécessaires.The article presents the priorities that appear in the local development strategies based on the valorization of the urban cultural heritage in the Medina of Fez. Two different approaches have been observed during the last decades. The first one is during the 1980-2000 period, when punctual and architectural actions prevailed in the Medina. The article debates the levels of responsibility and decision making in each period. The implication of the local, regional and national actors and the interest of the international organisms to the safeguard of this heritage, classified universal by the Unesco, have been observed. The second approach begun since 2000 and focuses on the regional plans and social development. Among the priorities of the action currently put in yard, the article presents the regional plans such as the PDRT (regional plan of the development of the tourism) and the PDRA (regional plan of development of the handicraft) and evokes the interest carried out to the rehabilitation of the urban architectural heritage and the struggle against the unsanitary habitat. The important needs expressed in this domain are in progress considering the Medina’s multiple degradation processes. The action of the local actors doesn’t manage to overcome these challenges due mainly, to financial problems. Interventions of more elevated levels are therefore necessary

Riesgo de inundaciones y estrategías de mitigación en los suburbios del sudeste de la ciudad de Fez (Marruecos)

The risk of flooding in the south-eastern suburbs of Fez (Morocco) was engendered by multiple factors (topographic, hydro-climatic, land use, social, technical). This study focuses on the Aouinate El Hajjaj district and shows that the district’s evolution, characterized by informal transactions (speculation, land squatting, construction without respect of norms and regulations) was a major factor in the genesis of flood risk as the district extended into vulnerable sectors. Public efforts to resolve the district’s crisis and reinforce its environmental safety began in 1993 (2 dams and channels were constructed, street were paved and basic facilities were provided, such as drinking water, sanitation and electricity), but the risk factors persist. Technical solutions are locally recognized to be useful, but they are not sufficient. Other mitigating actions including the reduction of physical and socioeconomic vulnerability and the strengthening of the social structure of the community should be considered in a systemic point of view. They constitute elements of an alternative strategy in urban planning and development and must be framed by laws and regulations. Their use could be undertaken at individual, community and State levels depending on the specific dimension of each measure. A vision which integrates local and regional scales is essential in risk studies, in order to design a more sustainable action. The role of non-governmental organisations is important in flood mitigation and urban environmental policy. The incorporation of flood prevention as a parameter of urban planning should be considered by planners and the local population.En los suburbios del sudeste de Fez (Marruecos) el riesgo de inundaciones responde a fenómenos de diversa naturaleza física y humana (topográficos, hidrológicos, climáticos, utilización del suelo, factores sociales y técnicos). En este trabajo se analiza la situación del distrito de Aouinate El Hajjaj, en donde diferentes procesos derivados de la ocupación de este espacio (especulación, proliferación de asentamientos informales, edificación sin respeto a las normas y reglamentos…) han constituido factores decisivos en la génesis de los riesgos de inundación que actualmente afectan a la zona. Aunque los esfuerzos públicos para resolver la crisis del distrito y reforzar su seguridad frente a las adversidades del medio natural comenzaron en 1993 (construcción de dos presas y de canales, pavimentado de calles, dotación y mejora de los equipamientos básicos como el abastecimiento de agua potable y de electricidad, obras de saneamiento, etc.), los factores de riesgo aún persisten. Las soluciones técnicas aplicadas han sido reconocidas por su utilidad, pero es necesario trabajar en otros ámbitos, como la reducción de la vulnerabilidad física, social y ambiental, y en el reforzamiento de la estructura social de la comunidad, lo que permitiría abordar el problema desde un punto de vista sistémico. Todos ellos constituyen los elementos de una estrategia alternativa en la planificación y el desarrollo urbano que deben ser enmarcadas por leyes y reglamentos. Su uso podría llevarse a cabo a nivel individual, comunitario y estatal —en función de la dimensión específica de cada caso—, con el fin de fomentar una estrategia de integración entre las escalas locales y regionales que contribuya a concebir acciones más sostenibles en los estudios de mitigación de los riesgos ambientales. Así mismo, el papel de las organizaciones no gubernamentales es importante en esta cuestión, y la política medioambiental, las acciones de los diferentes agentes que intervienen en el planeamiento urbano y la población local, deben estar sensibilizados y comprometidos con las estrategias para la prevención de inundaciones. [fr] Le risque d’inondation dans les banlieues du Sud-Est de la ville de Fez (Maroc) sont produits par des facteurs multiples (topographiques, hydro-climatiques, relatifs aux usages du sol, sociaux, techniques). L’étude vise le district d’Aouinate El Hajjaj et montre que son évolution, résultat de transactions informelles (spéculation, occupation illégale de terres, constructions ne respectant pas les normes et les régulations), a joué un rôle majeur dans la naissance du risque d’inondation au fur et à mesure que le district s’étalait vers des secteurs vulnérables. Les efforts des autorités pour donner une solution à la crise du district et renforcer sa sécurité environnementale ont commencé en 1993 (construction de deux barrages et de canaux, pavement des rues, dotation d’infrastructures essentielles comme l’eau potable, assainissement et électricité), mais les facteurs de risque existent toujours. Les solutions techniques sont considérées utiles localement, mais elles ne sont pas suffisantes. D’autres actions correctrices, comme la réduction de la vulnérabilité physique et socioéconomique ou le renforcement de la structure sociale communautaire, devraient être envisagées d’un point de vue systémique. Elles représentent des éléments d’une stratégie alternative dans l’aménagement et le développement urbain et elles doivent être encadrées par des lois et des régulations. Elles peuvent être entreprises aussi bien à l’échelle individuelle ou communautaire que par l’État, selon la dimension spécifique de chaque mesure. La vision qui intègre l’échelle locale et régionale est essentielle pour l’étude des risques afin de concevoir une action plus durable. Le rôle des organisations non gouvernementales est important dans la mitigation des inondations et la politique environnementale urbaine. L’incorporation de la prévention des inondations comme un paramètre de l’aménagement urbain doit être prise en compte par les planificateurs et par les populations locales

Les travertins du Moyen Dadès (cuvette de Ouarzazate, Maroc)

Akdim Brahim. Les travertins du Moyen Dadès (cuvette de Ouarzazate, Maroc). In: Méditerranée, troisième série, tome 57, 1-2-1986. Travertins LS et évolution des paysages holocènes dons le domaine méditerranéen. pp. 180-183

Genèse des carbonates terrestres dans la dépression de Quarzazate (Maroc méridional).

The carbonate encrusting process and its consequent products (crusts, tufa and travertine) in the southern Morocco (Ouarzazate) are studied in this thesis. A detailed inventory of the carbonate deposits is given. The dynamic aspects of carbonate precipitation and dissolution are considered from an environmental point of view. The main factors influencing their genesis are discussed on the basis of a multidisciplinary investigation. Among the accumulated carbonates, caliches are the most abundant. Their genesis invokes a changing environment where sedimentation has the same importance as the biogenic and pedogenic processes. Dated by the Uranium/Thorium method, these caliches are older than 300 ka. They indicate that the encrusting process is ancient. These deposits have become progressively rare during the Quaternary period except for the important hydrothermal travertine of Skoura. Only a few accumulations are still forming nowadays (Ait Arbi and Ifesfas). Their absence in present day water, especially in rivers is interpreted as indicating an environmental change. It is hypothesised that a desequilibrium affects the incrusting process. A comparative study between rivers and sources in different settings is carried out. The saturation degree of water, its chemical composition, especially in elements that may have particular origins (potassium, nitrate, sulfate, etc.) and its bacteriological characteristics are investigated in the thesis. Results seem to indicate that differences exist between the calcite - precipitating waters of some sources (not affected by human activities) and the sterile waters of rivers (Dades and M'goun). The latter are polluted by chemical fertilizers or turbulent, such that no carbonate deposits are permitted. The conclusion is that the reduced incrusting phenomena indicate an environmental change. A progressively drier climate and progressively reduced discharge make the deposits more limited in space and rare. The human impact on the quality of water must be considered to explain the limited extend of present day encrusting processes

Environmental vulnerability and agriculture in the karstic domain: landscape indicators and cases in the Atlas Highlands, Morocco

After the brief presentation of the major karstic areas in Morocco, the article focused essentially on the Atlas mountains to investigate the impact of the agriculture on the natural systems equilibrium. Socio-economic changes (demographic pressure, escalation of the landscape use, utilisation of new techniques in water harvesting, etc...) have sometimes fathered mechanisms of degradation. Many indicators seem to reflect these mechanisms. The pedologic indicators, soil erosion, the hydrologic and geomorphic indicators, are apprehended to demonstrate existent correlation between different variables and the often negative impacts of land over-use in the karstic domain of the Middle Atlas

Structural and Electronic Properties of Carbon-Nanotube/Graphene Junction: A First-Principles Study

Recently, a junction made of single wall carbon nanotube and a single sheet of graphene has been fabricated on silicon oxide substrate [1]. Their Raman spectroscopy measurements showed an upshift of the radial breathing modes and G peaks of the nanotube attributed to the charge transfer (CT) at the junction. The direction of the CT was determined from the intensity ratio of 2D/G of graphene, decreasing as a function of G Raman shift, which suggest n-doping of graphene due to the presence of nanotube. Their theoretical work, using molecular dynamics simulation, ruled out the strain on carbon nanotube to be the cause of the Raman upshift. In this work, we perform density functional theory calculations, for a model of C(13,7)/graphene junction, as suggested in Ref. [1]. Figure-1 shows the adopted model with 1132 carbon atoms, rendering the conventional first-principles methods that scale as O(N3) impractical. Therefore, we carried out the optimization of the large model using self-consistent density functional tight-binding method (SCC-DFTB), provided within CP2K package [2]. The resulting structure was then used to perform a single point energy calculation within density functional theory (DFT), adopting B97-D functional [3, 4], suitable for non-covalent interactions. The DFT is based on QUICKSTEP [5], which is an order-N method implemented in CP2K. Our preliminary results indicate that the charge transfer for a suspended nanotube/graphene system takes place from graphene to the carbon nanotube. To ascertain these results, we built a small material model consisting of the armchair C(10,10) and graphene junction, and performed calculations with the VASP package using optPBE [6] functional, which also includes the dispersion to account for van der Waals interactions. The results for the small model suggest an n-doping of carbon nanotube. Our findings are in agreement with the work of Cook et al. [7] for a C(8,0) adsorbed on a flat graphene junction. As can be seen, all the theoretical work seem to be in disagreement with the charge transfer direction, suggested in Ref. [1], which may be due to the pristine nature of the models. In this paper we will report on structural and electronic properties of a CNT/graphene junction, for pristine models as well as doped systems with impurities, where charge re-distribution at the junction will be outlined. 1. Geraldine L. C. Paulus, et al., Charge Transfer at Junctions of a Single Layer of Graphene and a Metallic Single Walled Carbon Nanotube. Small, 2013. 9: p. 1954. 2. CP2K. Available from: http://www.cp2k.org. 3. Grimme, S., Semiemperical GGA-type density functional constructed with long-range dispersion correction. J. Comput. Chem., 2006. 27: p. 1787. 4. Becke, A.D., Density-functional thermochemistry. V. Systematic optimization of exchange-correlation functionals. J. Chem. Phys., 1997. 107: p. 8554. 5. J. VandeVondele, et al., QUICKSTEP: Fast and accurate density functional calculations using a mixed Gaussian and plane waves approach. J. Comput. Phys. Commun., 2005. 167: p. 103. 6. Klimes, J., D.R. Bowler, and A. Michaelides, Van der Waals density functionals applied to solids. Phys. Rev. B, 2011. 83: p. 195131. 7. Brandon G. Cook, William R. French, and a.K. Varga, Electron Transport properties of carbon nanotube-graphene contacts. Appl. Phys. Lett., 2012. 101: p. 153501. </jats:p